Let’s look at what goes on in the brain during sex and orgasm. Although you think everything happens between your legs, the sensation of orgasm actually originates between your ears, in the form of chemical messengers and the receptors they bind to. These neurochemical changes take place in the limbic system, or "mammalian brain." The mammalian brain controls almost all bodily functions. It’s the seat of emotions, desires, drives and impulses. It’s where you fall in and out of love…or lust.

The mammalian brain is largely the same in all mammals. It has been around for well over 100,000,000 years, lurking right beneath your large, rational neo-cortex. Thanks to your limbic system, you cannot will your feelings, emotions, falling in love, or staying in love, anymore than you can will your heart to beat, or yourself to digest a meal or sleep.

Recently, scientists have begun to unravel the neurochemistry of falling in love. And, if there is a neurochemical program to fall into love (or lust), there must be one to fall out of love. For every biological event in your body, there is a biological cause. In this case, the cause is neurochemicals and receptors.

Neurochemical Commands

The most important factor in falling in - and out - of love is dopamine. Dopamine is the neurochemical that activates your reward circuitry. The reward center is a small portion of the limbic system, but it drives nearly all of your behaviors. This center is activated when you engage in activities that further your survival, or the continuation of your genes. Whether it’s sex, eating, taking risks, achieving goals, or drinking water, all increase dopamine, and dopamine turns on your reward center. You can think of dopamine as the "I’ve got to have it" neurochemical, whatever "it" is. It’s the "craving" neurochemical.

The more dopamine you release and the more your reward center is activated, the more "reward" you experience. A good example is food. We get a much bigger blast of dopamine eating high-calorie foods than we do low-calorie foods. It’s why we choose chocolate cake over Brussels sprouts. Our reward center is programmed so that "calories equal survival." You’re not actually craving ice cream, or a winning lotto ticket, or even a romp in the sack. You’re craving the dopamine that is released with these activities. Dopamine is your major motivation, not the item or activity.

Addiction mechanisms are complex, yet the one aspect they share is dopamine. All addictive drugs and all addictions increase dopamine; that is why they are addictive. Porn, accumulating money, gaining power over others, gambling, compulsive shopping, video games…if something really boosts your dopamine, then it’s potentially addictive for you. Why did Martha Stewart risk everything for more money? She got a thrill from a stock market gamble, and that gave her more dopamine. She didn’t need the money.

Do not get the idea that dopamine is bad. Dopamine is absolutely necessary for your survival. Yet when it’s too low or too high it can cause real problems. If you look at this chart you can see some behaviors and conditions associated with dopamine levels that are too high or too low. The key word on the list below is bonding. Bonding is more than a behavior. It is a mammalian program, the program that permits parenting and living in groups. When dopamine drops, you are likely to find your partner less rewarding - your bond unravels.

Dopamine Levels

Researchers placed electrodes in rats’ reward centers to stimulate them, just as dopamine does. The rats could then press a lever to stimulate the reward center. That’s all those rats did; they ignored food, and even female rats. They just sat there pressing the lever over and over, wasting away…not unlike crack addicts. In a second experiment, scientists blocked dopamine so the reward center could not be stimulated. What happened? The rats just sat there, again ignoring food, receptive mates, and the opportunity to explore their environment.

Orgasm is the biggest blast of dopamine (legally) available to us. A Dutch scientist recently scanned the brains of people having orgasm. He said they resembled scans of heroin rushes. He saw visions of an "orgasm pill" and lots of money. We saw visions of one of the most addictive substance ever produced.

Orgasms and addictions have two things in common. They both produce an initial pleasurable experience, and both are followed by an unpleasant hangover. The sexual satiation (orgasm) hangover is innate. It can be such a subtle part of you that you do not connect the dots--unless you switch to making love without it for several weeks, and then go back to sex with orgasm. "What goes up must come down." It’s simple biology; body systems must return to balance, or homeostasis. What goes up and down in this case is your dopamine. That can play havoc with your mood and the way in which you perceive, and treat, your partner.

With conventional sex and orgasms you’re going in and out of these dopamine extremes. So are we saying that orgasm makes you schizophrenic and then depressed, as in the chart above? No, but it definitely affects your behavior and mood. Not long after Gary (author of this article) got off of the orgasm/dopamine roller coaster, his lifelong chronic depression disappeared. Considering the behaviors associated with high and low dopamine may help explain how one’s lover can do the "Dr. Jekyll and Mr. Hyde" thing.

More to the Story

The highs and lows of dopamine are only part of the "post-sexual satiation hangover" story. At orgasm, dopamine drops like a lead balloon, and we lose interest, at least temporarily. However, if dopamine’s not kept in check, it could rapidly shoot up again and we’d be back in the sack. Biology’s mission is now to stop us from screwing around and place our attention elsewhere - like on hunting and gathering, feeding the babies, going to our job, taking out the trash and so forth. Otherwise we’d end up like those rats, working our levers over and over, and doing nothing else.

Suppressing dopamine is so important that nature uses an additional neurochemical to curtail our sexual desire. It’s called prolactin. If dopamine is the "foot on the gas," then prolactin is the "foot on the brake."

Dopamine - Prolactin Relationship at Orgasm

Dopamine- RED / Prolactin- BLUE

Research shows that prolactin surges immediately after orgasm in both men and women. Men may experience this prolactin surge as the "roll over and snore" phenomenon. In women, the effects may be delayed for days. We notice that the effects come and go for about two weeks.

There’s an inverse relationship between the levels of prolactin and dopamine; when one is up the other is down. This rise and fall produces a dopamine/prolactin roller coaster of highs and lows, and this roller coaster is a major part of the post-orgasm hangover.

What do couples complain of as their honeymoons end? The very symptoms associated with high prolactin: weight gain, drop in libido, mood changes, depression. Notice that in women excess prolactin is also associated with anxiety and hostility. Sound familiar? The following table lists symptoms of patients with chronically elevated prolactin. We think that after sex, the surges may be more subtle, but still noticeable in their effects.

Although research hasn’t shown how long prolactin surges continue in humans after sex, in female rats, twice daily surges of prolactin continue for up to two weeks. This may help to explain how great sex last week could lead to relationship friction now. And it’s no wonder we don’t make the link between cause and effect.

There’s also evidence that prolactin acts as a stress hormone. Unlike the "fight or flight" stress hormones, prolactin seems to be associated with "giving up," or "despair-type" stress. When a wild monkey is first caged, "fight or flight" stress hormones rise. As time goes by and despair sets in, "fight or flight" hormones fall and prolactin rises. Could these surges of prolactin explain agitation, wanting "space," or irritation with your partner that seems to come out of nowhere and then die down? Over time, could these recurring feelings also lead to relationship disillusionment?

To summarize thus far, orgasm leads to a drop in dopamine and a rise in prolactin. Both of these lead to multiple behavioral and emotional symptoms, which, in our experience, can arise over the next two weeks. During this time, behavior may change for the worse. More importantly, lovers' perception of each other can shift dramatically for the worse. If we feel depleted, our partner will seem overly demanding; if we feel needy, our partner will seem selfish and uncaring. Bickering and emotional separation then lead to further friction. Of course, few people ever avoid orgasm for two weeks. Most of us ride this roller coaster over and over, never really experiencing balanced brain chemistry - or the easy harmony that accompanies it.

Orgasm’s high dopamine/low dopamine pattern actually encourages addictions of many kinds because people attempt to use artificial means to manipulate their dopamine levels. Gary found that when he got off of the roller coaster, the results were amazing: dropping a long-term addiction and eventually leaving behind prescription antidepressants, ending a lifetime of depression.

Think about it. Most addictions kick in during teen years, when we become sexually active. A recent Columbia University study found that sexually active teens use more drugs. One might think social factors alone lead to this correlation between drugs and sex, but when scientists studied hamsters, they found that sexually-active hamsters were much more susceptible to amphetamine addiction than their virgin counterparts. This research brings us to another observation. Children, or pre-teens have yet to activate this dopamine roller coaster, and they possess a cheerful, optimistic enthusiasm for the simplest activities. Perhaps this is due to balanced dopamine.

Testosterone, Dopamine and the Coolidge Effect

There is further evidence for the post-passion hangover. Sexually-satiated male rats take up to fifteen days to recover their full desire for sex, although there is one way to jump-start them, which we’ll get to in a moment. Research shows they experience a reduction in testosterone receptors for up to a week within their reward circuitry. Hormones and neurochemicals dock with receptors on the nerve cells. In this case, fewer receptors mean less sensitivity to circulating testosterone. The result is that the reward circuitry pumps out less dopamine. If this happens in females, it would also reduce their sexual desire.

Low testosterone (or decreased sensitivity to it) is associated with irritability and anger. Serotonin and endorphin levels also rise in the reward circuitry of sexually-satiated rats. Most of us have heard that these are "happy neurochemicals," but in this particular part of the limbic brain both function to decrease dopamine and raise prolactin, respectively. Remember, ideal levels of dopamine are necessary for healthy bonds.

Humans, like virtually all mammals, are not naturally monogamous. This may not sound very romantic, but no mammals are sexually exclusive. (A few are socially monogamous. That is, they raise the pups together.) It is therefore likely that our mating neurochemistry is set up to accomplish two goals. It encourages bonding so we co-parent. Yet there is also a conflicting program to push us out of those bonds - at least far enough to add a novel mate.

From chimps to rats, the same neurochemical events drive mammalian behaviors, and they are driving them to be promiscuous. Is it likely that Mr. and Mrs. Rodent are growing apart in their relationship? Could the excitement be gone from their marriage? Perhaps Mrs. Chimp spends too much money, or nags too much. Maybe Mr. Chimp watches too much football or doesn’t help much with housework. Not likely. Just like us, they have a subconscious program, triggered by mating, hard-wired into their mammalian brains, which biology uses to urge them tire of their mates and move on to new mates.

During the two weeks that the hangover from orgasm lingers, our higher brain proposes logical reasons to explain our relationship disharmony. Orgasm is natural…absolutely. But it may also be natural for both men and women to sour on a mate, to suddenly find a spouse unattractive, irritating, and wholly unreasonable. It may even be natural to become wholly unreasonable and thus hasten the departure of a mate.

Now we know that all of you are wondering about that sure-fire way to jumpstart male rats' flagging libido. Perhaps you can already guess. All you have to do is introduce a new, receptive female. That may not be the answer you were hoping for…or perhaps it was!

Have you heard of the "Coolidge Effect?" Because that’s what we're addressing. Scientists have discovered that - after a frenzy of copulation - a male rat will lose interest in a female. BUT should a new female show up, he’ll perk up long enough to service her.¹ This process can be continued until he practically dies of exhaustion - once again proving that biology doesn’t give a rat’s…hindquarters about anything but propelling genes into the future. The Coolidge Effect has been observed in every species tested, and not just in males. Lady rodents prefer to seduce new guys, too.

The Coolidge Effect just might play a role in human affairs as well. Marnia once talked with a man who had stopped counting at 350 lovers. He said, "I really don’t understand it. I lost interest in all of them sexually so quickly - and some of those women are really beautiful, too."

The Coolidge Effect is linked to your post-orgasm hangover. The reason the rat loses interest is that he’s not getting any more dopamine surge from Partner No. 1. No dopamine, no interest. She is not perceived as "rewarding." The same thing happens to humans. The thrill is gone, and Partner No. 1 looks like Brussels sprouts. Now you’re primed for anything that will jack up your dopamine again. Partner No. 2 appears, and your dopamine soars. As if by magic, your blues are gone, and you have that heady feeling of anticipation, that sense of uninhibited aliveness. In short, No. 2 looks like chocolate cake.

What if No. 2 doesn’t show, and you’re left in the doldrums? Unlike rats, you have many dopamine-raising possibilities - from internet porn, gambling and alcohol - to the new dopamine agonists drug companies are producing to light a fire under slumbering libidos (not recommended, due to risky side effects).

These "fixes" make you feel better briefly, but as far as your well-being goes, they are like eating junk food - a net loss.

Your mammalian brain is not equipped to understand that there can be too much of a good thing. It just keeps rewarding you to do the same unrewarding things. A "fix" just positions you for a continuous addictive cycle of highs, more lows, and a search for more highs. Many of us spend much of our sex lives caught in this cycle - with no obvious way out.

The Power of Equilibrium

We have talked about how roller coaster levels of dopamine can break couples apart, but there’s also something holding couples together - at least at first. The neurochemical that binds couples together is oxytocin, the "cuddle hormone" or "bonding hormone." Without it, we could not fall in love. Falling in love is associated with a soup of neurochemicals - like adrenaline, which makes your heart race, and, as we have mentioned, dopamine, which makes you crave your beloved. But the heartwarming, loving, "gushy" aspects of love are due to oxytocin. It is the "unconditional love" hormone associated with nurturing and generous affection.

Oxytocin has various functions in the body, such as inducing labor contractions and milk ejection, but from evolutionary biology’s perspective, its main evolutionary function is to bond us to our children for life. It also serves to bond us to our mate…at least long enough to produce a child and (if we're lucky) get it on its feet.

Friendships are also built on oxytocin, and can be quite deep bonds. Yet, what happens to friendships that turn into sexual relationships? Often things change for the worse. This change is an excellent example of the post-sexual satiation neurochemical shift or hangover kicking in.

Oxytocin and dopamine are the yin and yang of bonding and love. You need both acting on the reward circuitry at ideal levels to stay in love. In experiments, if scientists block either oxytocin or dopamine, mothers will ignore their pups. There's evidence that these two neurochemicals stimulate each other's release, so if one is low, it affects levels of the other. As sexual satiation plays havoc with dopamine, lovers can end up with a double-whammy effect on their precious emotional bonds. Low dopamine alone interferes with feelings of love, and it may reduce oxytocin levels or the brain's sensitivity to oxytocin. As things go sour, something interferes with oxytocin's bonding effects. It's likely that it's low dopamine.

The good news is that making love while avoiding sexual satiation is the loophole in biology’s plan for our love lives. This is the secret that the ancient sacred-sexuality sages stumbled upon. Making love with lots of affection, without the dopamine-driven highs and lows of conventional sex, seems to keep neurochemical levels balanced.

The more oxytocin you produce, the more receptive you are to it. This is the opposite of dopamine. Addicts need more and more of a drug, which, of course, actually means they need more and more dopamine. Luckily you don’t need an ever-increasing "fix" of oxytocin to maintain the same gushy feeling. In fact, your partner just looks better and better - at least to you. This is why this practice can strengthen your bond with your mate.

When researchers injected oxytocin into the brain of a promiscuous breed of rodent, it preferred familiar partners to unfamiliar partners. Possibly the injection stimulates the production of dopamine or otherwise activates the animal's reward circuitry.

Oxytocin is associated with significant benefits, both emotionally and physically. In fact, oxytocin may be the answer to the question, "What is the mechanism by which love and affection positively affect our health?"

• Oxytocin reduces cravings. When scientists administered it to rodents who were addicted to cocaine, morphine, or heroin, the rats opted for less drugs, or showed fewer symptoms of withdrawal. (Kovacs, 1998)
• Oxytocin calms. A single rat injected with oxytocin has a calming effect on a cage full of anxious rats. (Agren, 2002)
• This quality of oxytocin explains why companionship can increase longevity - even among those who are HIV positive (Young, 2004). Or speed recovery: wounded hamsters heal twice as fast when they are paired with a sibling, rather than left in isolation (DeVries, 2004).
• It may also explain why, among various species of primates, care-giving parents (whether male or female) live significantly longer. (Cal Tech, 1998)
• Oxytocin appears be a major reason that SSRI’s [Prozac-type drugs] ease depression, perhaps because high levels of cortisol are the chief culprits in depression and anxiety disorders. (Oxytocin counteracts cortisol's effects.) (Uvnas-Moberg, 1999)
• Oxytocin increases sexual receptivity and counteracts impotence, which may be one reason why this other way of making love remains pleasurable. (Pedersen, C.A., 2002), (Arletti, 1997)

Again, notice that oxytocin reduces cravings and increases sexual receptivity. This allows making love without orgasm to be surprisingly satisfying. The affection is always there, flowing between you and your partner. When we tiptoe around dopamine’s highs and lows, we encourage balance and clear perception of each other. We see each other as sources of safety and pleasure, not as sources of stress. The real magic of love happens at a neurochemical level - and we can choose balance in order to foil the extremes of Mother Nature's plan.